Combustion of a fuel such as coal, oil, peat, waste, or the like, in a combustion plant such as a fossil power plant or a waste incineration plant, generates a hot process gas or “flue gas” containing among other components, gaseous pollutants, such as hydrogen chloride (HCl) and sulphur oxides (SOX), such as sulphur dioxide (SO2). It is normally necessary to remove at least a portion of the gaseous pollutants from the flue gas before releasing the flue gas into the atmosphere.
Separating gaseous pollutants such as hydrochloric acid and sulphur dioxide from flue gas is frequently accomplished using a DFGD system wherein a lime-containing absorbent material is introduced into the flue gas to react with the gaseous pollutants. When this lime-containing absorbent material reacts with the gaseous pollutants, the gaseous pollutants are converted chemically or physically into dust or particulate material, which is then separated in a filter. EP 1 815 903 A1 discloses an example of such a method, wherein a lime-containing dust is mixed with water in a mixer and then introduced into a contact reactor for reaction with flue gas gaseous pollutants. The dust or particulate material formed in the contact reactor is separated in a filter and recirculated to the mixer to be mixed again with water for subsequent introduction into the contact reactor.
Control of air pollution control systems, such as but not limited to DFGD systems such as that described above, WFGD systems, nitrogen oxide (NOX) removal via SCR systems, and particulate removal via ESP systems may be achieved using a multivariable model predictive controller (MPC) and a proportional integral derivative (PID) controller as disclosed in U.S. Pat. Nos. 7,640,067; 7,698,004; 7,860,586; 7,862,771; and 8,197,753; each incorporated herein in its entirety by reference.
To date, control of air pollution control systems using MPC and PID controllers require manual tuning. Manual tuning of such systems is time consuming, relatively expensive, prone to human variation and limitations, and the like. An automatic tuning control system for air pollution control systems is thereby considered desirable, preferable and necessary.